Information sharing led to a wide range of new complex applications in the Web environment, requiring a new way to formally represent knowledge and define a common vocabulary. Ontologies have recently been developed to provide a machine reasonable semantics of information sources that can be shared. The popularity of ontology development has increasing: it provides an information representation that supports enabling content-based access, knowledge modeling, interoperability, communications, and providing qualitatively new levels of knowledge representation in the form of the Semantic Web. Therefore, ontology can help professionals with a knowledge basis containing a proper semantic and validation rules. The oral rehabilitation has a directly impact of the patient life quality. Dental Implant treatment is complex and multivariable once diverse information must be proper shared and interpreted. A large number of dental implants failures due to an inappropriate definition. In this way, Dental Implant field has been continuously improved by the use of different techniques, methods and technologies in order to define the most efficient and effective diagnostic to the patient rehabilitation. The efficient and effective can be reached by enabling suitable decision-making in a shortest period of time, based on completed and updated information about the diagnostics. In this way, this research proposes a conceptual approach for making-decision using ontology concept and Multi-Criteria Decision Making/Analysis (MCDM/A) to support the dental implant definition. As results, the research presented a better picture of decision-making support in the Dental Implant field associate to engineering design. It is important the standardization and unification of knowledge by models that can be integrated, optimized and used as a referential for good practices.